source: trunk/npemap.org.uk/static/FAQ.html @ 389

Last change on this file since 389 was 389, checked in by Nick Burch, 15 years ago

Add some anchors to the FAQ

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1<!--#set var="title" value="FAQ" -->
2<!--#set var="link" value="/FAQ.html" -->
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4<!--#include virtual="inc/header.shtml" -->
5
6<h3>What is it?</h3>
7
8<p>There are a lot of applications on websites for being able to tell where
9people are from their postcode. For example "Where is my nearest
10B&amp;Q?". Unfortunately this data is expensive to licence (a few
11thousand pounds/year for a website). <a
12href="http://www.freethepostcode.org">Free the postcode</a> are doing a
13good job, but it is hard to contribute to their database as you
14need a GPS, so they have few postcodes.</p>
15
16<p>Our goal is to collect postcode data by getting users to locate
17themselves on a map of the country. They need only give the first part
18of their postcode, and if we can collect locations for all of these
19parts then we can create a database that is good enough for many
20applications. We are also accepting complete postcodes and 'partial'
21postcodes including the number portion of the second half of the postcode,
22in order to improve our accuracy.
23</p>
24
25<h3>What licence does the data have?</h3>
26
27<p>The data will be will be in the public domain; consequently, users
28submitting data agree to their submission being in the public domain
29when they enter their postcode.</p>
30
31<h3>Will I get more junk mail if I enter my postcode?</h3>
32
33<p>
34No, we are just interested in where the postcode is. We don't collect
35your name or house number. Please see our <a href="/privacy.html">privacy policy</a>.</p>
36
37<h3>What maps are you using?</h3>
38
39<p>We have scans of out of copyright OS maps of England and Wales.
40You can <a href="scotlandAndNI.html">register interest in future
41projects involving Scotland and Northern Ireland</a>.</p>
42
43<h3>So can I do what I like with your scans/tiles?</h3>
44
45<p>
46No. The scans and tiles have been placed under a
47<a href="tileLicence.html">licence</a>; they are not in the public
48domain.
49</p>
50
51<h3>Okay; I can use the tiles for some things; can I download the complete set?</h3>
52
53<p>
54Not yet. We need to make sure we've uncovered all the obvious flaws with
55the current tiles (eg human error in cropping and numbering the tiles)
56and have worked out an efficient distribution format.
57<a href="reportBug.html">Let us know</a> if you want to
58use the tiles; please don't try and crawl our tileserver to obtain the entire
59set.
60</p>
61
62<h3>Isn't orthowotsiting an old map hard?</h3>
63
64<p>Luckily we're going to work in the OSGB coordinate system that
65matches up with the grid lines on the map; this means we don't have to
66distort the maps too much. We also are not overly fussy about the
67accuracy, so this step can be done quickly.</p>
68
69<h3>Why don't you use maps created from <a
70href="http://www.openstreetmap.org">OpenStreetMap</a> data?</h3>
71
72<p>Because they are licensed under Creative Commons Share-alike
73licences, so we wouldn't be able to make our data public domain.</p>
74
75<p>There are people who believe that locating a point on a map creates a
76derived work, and hence requires a licence. We don't want to be the first
77to prove them wrong in a court, as that will be pricy.</p>
78
79<p>Also, the OpenStreetMap maps are not yet complete enough to achieve our
80goal of country-wide coverage.</p>
81
82<h3>Will this data be imported back into Free the Postcode?</h3>
83
84<p>Probably not directly. We are looking at the best way of presenting
85data from both projects whilst not polluting the Free the Postcode database
86with our lower accuracy data. We are importing Free the Postcode data into
87our database for display, but not re-exporting it currently.</p>
88
89<h3>If you are using scans of old maps, how accurate will the locations
90be?</h3>
91
92<p>Some of the scans are out by a degree or two but they are fairly
93good. We hope to be able to get better than 100 metres accuracy out of it in
94the end. This is more than good enough to locate a region as large as
95the first half of a postcode, and hopefully as much as the 'partial'
96postcodes described in the answer to 'What is it?' above.</p>
97
98<h3>My house isn't on a 1950s map</h3>
99
100<p>Find some local landmarks and guess where your house is. This is
101accurate enough for our purposes.</p>
102
103
104<a name="gps"></a>
105<h3>I know exactly where I am, and what my postcode is</h3>
106
107<p>If you have a GPS, enter your data into <a
108href="http://www.freethepostcode.org">Free the Postcode</a> and make the
109world a better place.</p>
110
111
112<a name="islands"></a>
113<h3>I can't seem to find a certain island on your overview map</h3>
114<p>We've put together a list of <a href="islands.html">hard to find
115 islands</a>, so you might well be able to find it from there.</p>
116
117
118<h3>So, how do I use it?</h3>
119
120<p>Find your location on our map, click where your postcode is, enter
121the postcode, agreeing to release your data.</p>
122
123
124<a name="codepoint"></a>
125<h3>Psst, I have a copy of the codepoint database. Wanna look?</h3>
126
127<p>No thanks, we want free data so we don't have to keep paying the nice
128codepoint people. </p>
129
130<h3>Won't you drive codepoint out of business?</h3>
131
132<p>We don't think so. There are a lot of places where this level of
133accuracy just isn't enough. Those people will still have to pay until
134<a href="http://www.freethepostcode.org">Free the Postcode</a> improves
135its coverage.</p>
136
137<h3>The map doesn't join up.</h3>
138
139<p>Yes, it isn't perfect. The OS didn't publish a single map of the whole
140country, so you have to scan then stick together data from several maps.
141We don't really know how to correct it perfectly. It would be really cool
142if someone could write software to detect the gridlines and automatically
143cut the images up on the lines and make them square.</p> 
144
145<h3>The wonkiness is so annoying it drives me mad, and I have experience of orthrectifying maps. Please let me straighten your maps.</h3>
146
147<p>Cool. Contact us, that would be great.</p>
148
149<h3>Why didn't you use proj/gdal?</h3>
150
151<p>Because we don't know how to work them. If you feel like improving how this
152works, let us know. Update: We do use proj for the <a href="/postcodeine/">postcode display</a>.</p>
153
154
155<a name="scotlandNI"></a>
156<h3>Why don't you have good mapping data of Scotland and Northern Ireland?</h3>
157
158<p>While the Ordnance Survey did create the New Popular Edition maps of
159 Scotland at 1 inch to the mile, these were never
160 published, so we can't buy them to scan in. All we have been able to get
161 is quarter inch to the mile maps, which don't fit into our tiling scheme,
162 and are too small for finding postcodes on.</p>
163<p>Scotland and Northern Ireland were included in the Ordnance Survey
164 7<sup>th</sup> Edition at 1 inch to the mile, but
165 almost all of these maps remain in copyright for another few years, so
166 we couldn't put them online.</p>
167<p>If you do have free higher resolution images of either of Scotland or
168 Northern Ireland (eg the 1920s Popular Edition, or the War Office Editions),
169 then we would be very interested. Do please contact us if you have such
170 maps.</p>
171<p>If you would like to be notified when we do get out of copyright 1 inch
172 to the mile maps of Scotland and Northern Ireland, please
173 <a href="scotlandAndNI.html">register your interest</a>.</p>
174
175
176
177<h3>Who did the work?</h3>
178
179<ul>
180<li>Richard Fairhurst acquired and scanned the maps,</li>
181<li>Dominic Hargreaves and David Sheldon straightened and tiled the maps,</li>
182<li>Matthew Westcott, <a href="http://www.earth.li/~dave/">David Sheldon</a>, Dominic Hargreaves and Nick Burch worked on the user interface and backend software.</li>
183<li>Nick, David and Matthew's employer <a href="http://www.torchbox.com">Torchbox</a> has supported the project with some development time and design work.</li>
184</ul>
185
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